A kind of energy receiver that could retrieve a soul from the radiation belt surrounding a planet.

In this remarkable novel, Roger Zelazny has created a world in which reincarnation really works. All of the electrical impulses that constitute a person can be successfully transferred from an old, infirm body to a new healthy one. The original settlers of the planet set themselves up as deities overseeing this system. One warrior who challenged the system was punished by being sentenced to nirvana - having his electrical being projected into the radiation belt surrounding the planet. At the beginning of the story, he is summoned back to life with a pray-machine.

It was in the days of the rains that their prayers went up, not from the fingering of knotted prayer cords ... but from the great pray-machine in the monastery of Ratri, goddess of the Night.

The high-frequency prayers were directed upward through the atmosphere and out beyond it, passing into that golden cloud ... which is seen as a bronze rainbow at night and where the red sun becomes orange at midday.

Yama tended the pray-machine and the giant metal lotus he had set atop the monastery roof turned in its sockets. For six days he had offered many kilowatts of prayer, but the static kept him from being heard on high.

Yama was successful, bring the protagonist of the novel back to life; the Mahasamatman, or as he called himself, Sam. This remarkable fusion of Indian epic, technology and typical tongue-in-cheek wit won Zelazny the Hugo award in 1968.

Here's another interesting tidbit:

"This day your sin account is filled to overflowing," said the sailmaker.

"But, ah, my prayer account!" replied the prince. "I'll stand on that for the time being. Future theologians will have to make the final decision, though, as to the acceptability of all those slugs in the pray-o-mats..."

It's interesting to note that in Tibetan Buddhism, prayer wheels (Chokhor) are turned by hand to gain merit, but larger ones are made to turn by wind power or water power, providing a kind of automated karmic gain.

Compare to the mother scanner from The Turning Wheel (1954) by Philip K. Dick.